Method of manufacturing condenser electrodes



June 1939- J. KIPPERMAN ET AL 2,161,419

METHOD OF MANUFACTURING CONDENSER ELECTRODES Filed Aug. 21, 1936 L 57- INVENTORS JAN KIPPERMAN AND ADRIAAN JAN [MN LAMBEEK MW ATTORNEY Patented June 6, 1939 2,161,419

METHOD OF MANUFACTURING CONDENSER ELECTRODES Jan Kipperman and Adrian Jan .lnrlaan Lamheek, Tllhurg, Netherlands, amlgnors to N. V. P hi I l p s Gloeilampcnfahrleken, Eindhoven, Netherlands Application sum 21. 1936. Serial No. 91.200

In Germany September 2, 1935 6 Claims. (Cl. 29-1555) The invention relates to a method of manufacthe width b of the zones of afllux would be equal turing condenser electrodes built up from a for all rings. plurality of concentric rings of substantially the When deforming in accordance with said obvisame height and with equal wall thicknesses andv ous idea, it is found that the inner rings are intervening spaces which rings are arranged on a formed only very imperfectly and the product common bottom. Condenser electrodes of this obtained is unfit for practical use. It appears kind are known already. The known electrodes therefrom that the resistance against deformaare manufactured by concentrically securing, for tlon strongly increases towards the middle. The example by soldering, a plurality of rings to a applicants have gained the recognition that the 10 common bottom, so as to be mutually concentric. zone of aillux which really occurs differs from the 10 It has also previously been proposed to manufac above-mentioned apparent zone of alliux. The ture the electrodes by arranging a plurality of real zone of afllux of a ring is to be understood cup-shaped bodies so as to be mutually concento mean the region from which originates the trio and to secure the bottoms thereof to one material of the rin u de co der t on.

another. The condenser is built up from two of On the ground of this recognition the ap- 15 such electrodes capable of being slid into one plicants have found that by giving the tool to be another. employed the correct shape the form of the real The invention consists in manufacturing the zones of afllux can be acted upon in such manner whole of the electrode from a single piece of that the final shape of the body to be produced material in a single operation with the aid of the can be determined beforehand, go "cold squirting process which is known per se. According to the invention, the apparent zone The cold squirting process is utilised, for exof afllux of the outermost ring is reduced. It has ample, in the manufacture of cup-shaped bodies been found that in this way the real zones of from a single piece of material, e. g., aluminium, alllux of all rings, from the inside to the outside,

the material being pressed through a single slit are reduced more and more. 5 (die). As'mentioned above, the resistance against de- 7 However, the manufacture of bodies of more formation increases from the outside to the incomplicated shape in which the material is inside and the rings located further outwards simultaneously pressed through a plurality of take a larger height.

3 slits, is beset, as is well-known, with drawbacks When taking the measure di g .to the in- 80 which consist in that the desired deformation is vention the real zones of afllux of the different restricted to determined zones and is brought 111185 are acted p in Such manner that the about at other points only imperfectly or not t inward increase of the resistance, against deforall. This phenomenon is probably due to the n. which esu in the un qua he ht of fact that the material preferably flows towards the 8 is e t a ze and that bodies as those 86 the zones with the slightest resistances against ab ve described may be manufactured from a deformation or frictional resistances. For this n e piece of t a according t th coldreason the cold-squirting process has hitherto Squirting e od. remained restricted to bodies of simple shape. The invention will be explained more fully 40 According to the invention, by taking particular with reference to the accompanying drawing. 40 measures it becomes possible to, produce in this Although for the sake of simplicity only a slight way also bodies of very complicated shape. number of rings is shown; it is clear that in ac- The starting-point is formed by the following cordance with the invention electrodes may be considerations: On considering the article before manufactured which consist of any desired numand after deformation, one would expect the aillux ber of rings. 46 or cold flow of the material of each ring from Fig. 1 represents a condenser electrode conthat region of the material which has not yet slsting of a bottom I and of rings 2, 3 and l. The been brought into its final shape, which is located bottom is provided at the outside with a flange 5. in the immediate vicinity of the ring in question. It would be possible to turn such a body. Ac-

If. as indicated in Fig. 3, the distances between cording to the invention such a body is pro- 6 the rings are divided into two, it would be obvious duced with the aid of the cold-squirting process. that, when considering the zones between these As previously mentioned, this method is known lines of separation to be zones of afllux of the enfor squirting bodies of simple, e. g. cup-shaped closed rings, with these apparent zones of afllux form. Use is made in that case of a device conan equal height for all rings could be obtained if sisting of two parts. Building further on that 5 which is known, one arrives at the device shown in Fig. 2 which consists of a stationary table 8 and a movable stamp or die. A pastil or metal blank P is placed on the table. The stamp comprises a body pierced with a cylindrical aperture and a plurality of annular stamp portions 9 and I0. The body 1 has a widened portion Ii in which the flange is formed which is required for the easy removal of the body after the moulding operation. The applicants have found, however that such a mould would be completely unfit for use because there would be produced an electrode as shown in Fig. 3.

It is impossible to mould with this device in such manner that the inner rings, too, acquire a sufllcient height. The applicants have found that this phenomenon has to be ascribed to the causes mentioned hereafter.

Fig. 3 shows diagrammatically the apparent zones of aifiux. The apparent'zone of aillux P2 of the outermost ring is substantially equal to the apparent zones of ailiux i3 and ll of the rings located more inwards. It has been found, however, that with this mould the real zone of ailiux of the outer rings is much larger than that of the inner rings and that the extension of the real zones of afllux decreases inwardly. This phenomenon results from the greater resistance against deformation experienced by the material in the neighbourhood of the rings located farther inwardly. According to the invention, this drawback may be removed by reducing the apparent zone of ailiux of the outermost ring. It has been found that this measure acts upon the real zones of ailiux of all rings in such manner that for each ring which is located more outwardly less material is available, owing to which all rings acquire a substantially equal height. This may be ensured, for example, by suppressing the annular cavity II in Fig. 2 which, on shallow consideration, would be required in order to obtain the desired shape. There is produced in this case a condenser electrode according to Fig. 4 which is smooth on the outside and whose rings have substantially the same height. It will be seen that the apparent zone of afiiux I5 of the outermost ring is smaller than the apparent zones of afilux l6 of the following rings. The apparent zones of afliux of the other rings are equal. There is produced in this way a central aperture with a narrowed portion which may be utilized, if desired, for the expulsion of the work-piece.

As results from the above, a radial displacement of the material during deformation is required in order to obtain the desired deformation. It is necessary for this purpose that in the achieved electrode the thickness of the bottom is large relatively to the thickness of the rings, for example four times as large. Slight disparities in the height of the rings may be compensated for in the manner usually applied in technics.

An electrode according to the invention having the flange 5 shown in Fig. 1 may be manufactured with the aid of the moulding device represented in Fig. 5. This device consists of a table I! and of a body l8 arranged thereon which does not move together with the stamp and which has an annular recess I 9. P denotes again the pastil. The stamp has a pin 20 and a few annular stamp portions 2i, 22 and 23. It has been found that with this mould, too, the apparent zone of aillux of the outermost ring is smaller than those of the other rings so that the desired effect is ensured. The lower surface of the bottom of the electrode may have any desired profile which is simultaneously pressed into it.

The applicants have found that the increase of the zone of aillux for the innermost ring, which may be obtained, for example, by suppressing or reducing the aperture in the bottom, acts almost exclusively on the deformation of the inner rings but does not extend to the rings located further outwards. A central aperture is consequently always indispensable. This does, however, not entail any disadvantage, for this aperture may serve very well for the attachment of the electrode in the condenser. This is particularly important with adjustable condensers. Through said aperture may be passed in this case, for example, a spindle on which the electrode is slidable.

The electrode according to the invention aiIords, in addition to its cheap manufacture, the further advantage that the distance between two rings is always the same. Besides, all electrodes manufactured with one and the same device, are exactly identical so that the disparities in the values of the capacities of different condensers may be kept very small.

As the material may be utilised first of all aluminium and then also content of copper, lead and zinc. In general any material utilised in cold-squirting may be, employed. A previous heating of the pastil may be advantageous. If use is made of aluminium, the heating temperature should preferably amount to about 200 C.

What we claim is:

l. Themethod of making a condenser electrode having a. smooth outside wall and a plurality of rings of substantially the same height from a single piece. of metal by cold squirting process which comprises placing a circular blank of metal on a stationary table and confining said blank within a circular body arranged on said stationary table, forming said blank of metal by applying pressure on a movable die having a central guide pin, and a plurality of annular rings, the arrangement of each ring being such that the real zones of aifiux of all of the rings from the inside to the outside are reduced more and more toprovide equal height of the rings thus formed.

2. The method of making a condenser electrode from a single piece of metal by cold squirting process which comprises heating a blank of aluminum metal to approximately two hundred degrees centigrade, placing said aluminum blank on a stationary table, minum blank within a circular body arranged on said stationary table, forming said blank of aluminum by applying pressure on a movable die having a central guide pin, and a plurality of annular rings, the arrangement of each ring being such that the real zones of aillux of all the rings from the inside to the outside are reduced more and more to provide equal height of the rings thus formed.

3. The method of making a condenser electrode from a single piece of metal by cold squirting process which comprises placing a circular blank of metal on a stationary table and con fining said blank within a circular body arranged table, forming said blank of metal by applying pressure on a movable die having a central guide pin, and a plurality of annular rings, the arrangement of each ring being such that the apparent zone of aillux of the metal of the outer ring is reduced so that the real and confining said aluill sonesoiaiiiuxoialltheringsiromtheinaide totheoutsidearereducedmoreandmoreto provide equal height 0! the rings thus formed.

4. The method of making a condenser electrode having a thickness which is large at the bottom relative to the thickness of a plurality of rings, from a single piece or metal by cold squirting process which comprises placing a circular blank of metal on a stationary table and conlining said blank within a circular body arranged on said stationary table, forming said blank 0! metal by applying pressure on a movable die having a central guide pin, and a plurality oi annular rings, the arrangement oi each ring being such that the real zones 01' aillux of all the rings from the inside to the outside are reduced more and more to provide equal height of the rings thus formed.

5. The method of making a condenser electrode having its thickness at least four times as large at the bottom relative to the thickness of a plurality of rings, from a single piece of metal, bycoldsquirtingprocesswhichcomprimplacing a circular blank oi metal on a stationary'table asandconiiningsaidblankwithinacircularbody arranged on said stationary table, forming said blank of metal by applying pressure on a movable die having a central guide pin, and a plurality oi annular rings, the arrangement of each ring being such that the real zones of ailiux of all the rings from the inside to the outside are reduced more and more to provide equal height oi the rings thus formed.

8. The method of making a condenser electrode from a single piece of metal by cold squirting process which comprises placing a circular blank 0! metal having a central aperture on a stationary table and confining said blank within a circular body arranged on said stationary table, forming said blank oi metal by applying pressure on a movable die having a central guide pin, and

-a plurality of annular rings, the arrangement of each ring being such that the real zones of aiilux of all the rings irom the inside to the out side are reduced more and more to provide equal height of the rings thus formed, the central guide pin passing through the aperture in said guide.

JAN WAN.

ADRIAAN JAN JURIAAN LAMBIIK. 

